They gave you the "how do i"

"To update your EFIN to include 1040 Modernized e-file returns, please copy and paste this web address in an internet browser to go to IRS e-Services where your EFIN can be updated online. https://la.www4.irs.gov/e-services/Registration/index.htm Or you may also call the IRS e-File Helpdesk for assistance at: (866) 255-0654"